1. Field of the Invention
This invention relates to a novel retainer for straps. In particular, the invention relates to a locking ring for straps used as seat belts for infants and small children in shopping carts or other vehicles.
2. The Prior Art
Shopping carts are often equipped with safety belts for securing a child in the seating area. The belts are typically a length of nylon webbing that is secured to the cart with a metal or plastic D-ring.
One such device is shown in U.S. Pat. No. 5,669,118 to Frano et al. This patent discloses a strap retainer in the form of a locking D-ring. The ring comprises a straight post and an integrally-formed arcuate retainer element that is snapped on to the post to lock the ring closed. The locking element comprises a protruding nail-like head on the post that slips into a keyhole shaped aperture in the arcuate retainer element.
Many manufacturers of child seat belts prefer to ship the belts with the strap retainers attached, for easy assembly onto the shopping carts at their destination point. The disadvantage of using the prior art strap retainer is that the strap can easily slide off of the open post during shipping. This would result in an unnecessary expenditure of time and effort reassembling the straps and retainers at their destination point.
Another disadvantage of the prior art strap retainer is its inability to withstand high amounts of tension. The locking elements are arranged at a 90.degree. angle to the direction of force on the ring. This creates the risk that the locking elements, especially the nail-like head on the post, will break under high amounts of stress.
A solution to this problem was proposed by U.S. Pat. No. 5,781,970 to Anscher. This strap retainer comprises a triangular body having the locking elements arranged along the middle of one leg of the triangle. The locking elements are disposed at 180.degree. to each other, so that the direction of force is along the longitudinal axis of the locking elements. The locking elements are comprised of a locking pawl that slides into a receptacle and is locked in place by a locking tooth on the bottom of the receptacle. While this arrangement leads to an exceptionally strong strap retainer when used in a normal way, this strap retainer is unable to withstand unusual twisting and torque, which may occur when shopping carts are smashed together as they are being collected. Placing a twisting force onto the locked retainer can cause the locking pawl to become disengaged from the receptacle and free the strap from the shopping cart.